Electrical connectors



May 5, 1970 F, WIELAND ELECTRICAL CONNECTORS- 2 Sheets-Sheet 1 Filed Nov. 18, 1968 I 6 IIIIIIIII/IIIII 1 F'i g. 9

g Fig.5 9

Fig. 70

if 4 4 M411 F. WIELAND May 5, 1970 ELECTRICAL CONNECTORS 2 Sheets-Sheet 2 Filed Nov. 18, 1968 Fig.72

RoWw 2mg sw n WWMW Ffmm n M 3 M; mg m F 5 m F 3,510,830 Patented May 5, 1970 3,510,830 ELECTRICAL CONNECTORS Friedrich Wieland, 14 Brennerstrasse, Bamberg, Germany Filed Nov. 18, 1968, Ser. No. 776,433 Claims priority, appligstion Gsrmany, Mar. 9, 1968,

Int. Cl. H01r9/10, 7/12 US. Cl. 339-198 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The invention relates to electrical connectors of the straight throng type comprising a metal connector body and clamping screws and, possibly additional fixing screws, located in an insulating casing.

Such connectors must satisfy several requirements. All the clamping screws must be reliably locked to prevent them from working loose when the connector is subject to vibration. Moreover, the metal connector body must not drop out of the shell-like insulating casing which is open on one side, even when the connector is fitted, as may often be necessary in installational work, with the open side downwards.

Many proposals have already been made for solving the problem of securing clamping screws so that they cannot work loose. Generally speaking, spring washers or spring clips are used for such purposes. They cooperate with the screws but, because of their deformation resistance, they are apt to impair the surface protection of the screws and they may frequently even damage or destroy the screw threads. A further drawback is that for securing the screws in this way a special additional part is required for each screw.

So far as locating the connector body inside the casing is concerned, the proposal to do this by means of an adhesive is not satisfactory because the adhesive film is not always reliable. Another proposal, namely, to provide the metal connector body with a ribbing that is stripped off when the metal body is fitted into the insulating casing so that the body is thereafter held in position in a completely tight fit is likewise not satisfactory because this method of location ceases to be effective if the metal connector body is temporarily only once taken out. As a matter of experience this cannot usually be avoided during installation.

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is therefore the provision of an electrical connector of the straight through type in which the screws are reliably secured in a manner preventing them from working loose and the connector body is located in the insulating casing so that it cannot drop out. Moreover, an object of the invention is to achieve this result without associating additional components with the screws.

According to this invention there is provided an electrical connector of the straight through type and comprising an insulating casing open at one side, a metal connector body located in the insulating casing, and clamping screws which screw into the connector body, the insulating casing being of an elastic synthetic plastics material and being formed with web means having holes through which the screws pass, the holes having a diameter which is smaller than the major diameter of the screw threads.

In a connector in accordance with this invention the screws cannot work loose, since the web means through which they pass and which are integrally formed with the casing also consist of the elastic plastics material and therefore grip the screws in a manner preventing rotation. With this arrangement the screws which are thus located also hold the metal connector body in its position of use. The connector in accordance with this invention has the advantage that the insulating casing is used to perform the function of securing the screws and of locating the connector body besides fulfilling its primary function of insulating the connector.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a connector embodying this invention;

FIGS. 2 and 3 are respectively a side view and a plan view of the connector shown in FIG. 1;

FIG. 4 is a front view, partly in section, of an insulating casing a of the connector shown in FIG. 1;

FIG. 5 is a plan view of the insulating casing a;

FIGS. 6 and 7 are sectional views at right angles to each other of a connector body b of the connector shown in FIG. 1;

FIG. 8 is a side view of a clamping screw d;

FIGS. 9 and 10 are respectively side and plan views of a safety clip i;

FIG. 11 is a front view of another connector embodying this invention;

FIGS. 12 and 13 are respectively a side view and a plan view of the connector shown in FIG. 10;

FIGS. 14 and 15 are respectively a front view (partly in section) and a plan view of an insulating casing b of the connector shown in FIG. 10;

FIGS. 16 and 17 are sectional views at right angles to each other of a metal connector body b of the connector shown in FIG. 10;

FIG. 18 is a side view of the clamping screw :1;

FIGS. 19 and 20 are respectively a side view and a plan view of the safety clip i;

FIG. 21 is a side view of a clamping screw m; and

FIGS. 22 and 23 are respectively a cross section and a plan view of a connecting strip n.

DETAILED DECRIPTION OF THE PREFERRED EMBODIMENT The connector shown in FIGS. 1 to 10 has an insulating casing a which is of an elastic synthetic plastics material and in which a metal connector body b is located. The connector body b is provided with two tapped holes c which receive the two clamping screws d. The insulating casing has the shape of a shell, i.e. one side thereof is open. The connector body b has a central recess e which receives a web f formed in the insulating casing a.

Webs g are integrally formed with the insulating cas ing a and are provided with holes h through which the clamping screws pass and which have a diameter slightly less than the major diameter of the screw threads. These webs g therefore grip the screws d and prevent them from accidentally working loose.

By examination to the drawings it will be clear that this arrangement not only stops the screws d from accidentally loosening but also ensures correct location of the connector body b.

Means can be provided to ensure that the screws d cannot be accidentally screwed completely out of the holes h in the webs g. For this purpose safety clips i may be provided, each safety clip 1 being recessed at k so as to fit into a peripheral groove l in an individual screw d when that screw d has been screwed into the body b of the connector.

The clamping screws d shown in the embodiment shown in FIGS. 1 to 10 are similar in the embodiment shown in FIGS. 11 to 20. In this embodiment the metal connector body 12 contains an additional centrally disposed clamping screw m which locates a metal connector strip n for'making connections to neighbouring connectors. The screw m passes through a web which is integral with the insulating casing a and which contains a bore p the diameter of which slightly less than the major diameter of the thread of the screw m.

Before the connecting strip n is inserted a portion of material must be broken out of the wall of the insulating casing a to form the recess q. Marginal indentations r (FIGS. 1, 3, 4 and are provided in the casing a to facilitate fracture of the casing a to provide the recess q.

The clamping screw m may also be used to locate a cross connecting bridge, an instrument tapping or the like instead of the illustrated connecting strip.

While the present invention has been described with reference to particular embodiments, this description is intended in no way to limit the scope of the invention.

What is claimed is:

1. An electrical connector of the straight through type and comprising an insulating casing open at one side, a metal connector body located in the insulating casing,

4 and clamping screws which screw into the connector body, the insulating casing being of an elastic synthetic plastics material and being formed with web means having holes through which the screws pass, the holes having a diameter which is smaller than the major diameter of the screw threads.

2. An electrical connector as claimed in claim 1 wherein a clip is secured to the end of each screw and so retains that screw.

3. An electrical connector as claimed in claim 1 which also comprises at least one fixing screw which passes through one of said holes and screws into the connector body.

4. An electrical connector as claimed in claim 1 wherein said web means comprise a plurality of webs.

References Cited UNITED STATES PATENTS 2,292,195 8/ 1942 Brown 41 3,260,989 7/1966 Curtis 151-69 X FOREIGN PATENTS 765,594 10/1952 Germany. 1,071,808 12/1959 Germany.

MARVIN A. CHAMPION, Primary Examiner R. A. HAFER, Assistant Examiner US. Cl. X.R. 

